Metal passivation/SOX control compositions for FCC

ABSTRACT

A composition comprising a coprecipitated magnesia-lanthana-alumina (MgO--La 2  O 3  --Al 2  O 3 ) wherein the MgO component is present as microcrystalline phase, having a BET (N 2 ) surface area of at least 130 m 2  /g, preferably part of which contains a catalytic oxidation and/or reducing promoter metal such as ceria, vanadia, iron and/or titania, is combined with an FCC catalyst which is used to catalytically crack a hydrocarbon feedstock that contains metal and/or sulfur.

This application is a continuation-in-part of my U.S. Ser. No. 831,610,filed Feb. 5, 1992, now U.S. Pat. No. 5,288,675, and 959,023 filed Oct.9, 1992, and now abandoned.

The present invention relates to compositions which are used to controlSOx emission and the adverse effects of metals such as V and/or Niencountered in fluid catalytic cracking (FCC) operations, and moreparticularly to compositions that passivate Ni and/or V during thecatalytic cracking of hydrocarbons as well as control SOx emissionsduring oxidation regeneration of the catalysts.

Compositions which have been used to passivate Ni and/or V as well ascontrol SOx emissions typically comprise magnesia, alumina and rareearth oxides.

In particular, U.S. Pat. No. 4,472,267, U.S. Pat. No. 4,495,304 and U.S.Pat. No. 4,495,305 disclose compositions which contain magnesia-aluminaspinel supports in combination with rare-earths such as ceria andlanthana, and U.S. Pat. No. 4,836,993 discloses the preparation ofmagnesium aluminate (MgAl₂ O₄) and magnesia-alumina composites that arecombined with a rare earth and used as sulfur oxide absorbent in FCCprocesses.

While prior compositions have been successfully used to control theadverse effects of V and/or Ni as well as the SOx emissions from FCCunits, the industry requires compositions that are efficient for thepassivation of V and/or Ni which is present in hydrocarbon feedstocks.

In addition, V and/or Ni/SOx control agents which are used in the formof separate particulate additives must have hardness and attritionproperties that enable the additive to remain in a circulating FCCcatalyst inventory.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide novelSOx gettering agent/metals passivation compositions.

It is another object to provide metal control additives for use in FCCprocesses that are also efficient for SOx pick-up and release as well asthe passivation of V and/or Ni.

It is a further object to provide magnesia-lanthana-alumina containingmetals/SOx control additives that are resistant to attrition and capableof maintaining sufficiently high surface area when used in the highlyabrasive and hydrothermal conditions encountered in a commercial FCCprocess.

It is yet another object to provide efficient/economical methods forpreparing metals/SOx control additives on a commercial scale.

These and still further objects will become readily apparent to oneskilled-in-the-art from the following detailed description, specificexamples, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are block diagrams which illustrate preferred methods forpreparing the novel composition of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Broadly, my invention contemplates a novel nonspinel, ternary oxide basehaving the formula (expressed in weight percent calculated as theoxides):

30 to 50 MgO/5 to 30 La₂ O₃ /30 to 50 Al₂ O₃ wherein the MgO componentis present as a microcrystalline phase which is particularly effectivefor passivating V and/or Ni as well as controlling SOx emissions duringthe catalytic cracking of hydrocarbons.

More specifically, my invention comprises a novel MgO/La₂ O₃ /Al₂ O₃ternary oxide base which is preferably combined with catalytic oxidationand/or reducing promoters such as oxides of Ce, V, Fe and/or Ti incombination with zeolite containing catalytic cracking compositionswhich are used to process hydrocarbon feedstocks that contain Ni/Vand/or sulfur.

The preferred additive compositions are further characterized by: Afresh surface area of 100 to 300 m² /g following 2-hour air calcinationat 538° C., and preferably 130 to 260 m² /g as determined by the B.E.T.method using nitrogen; a surface area of 100 to 200 m² /g upon 48-hoursteaming with 20% steam/80% air; a pore volume of 0.4 to 1.0 cc/g asdetermined by water; a nitrogen pore volume of at least about 0.3 cc/g,preferably 0.4 to 0.6 cc/g from nitrogen porosimetry covering up to 600Å pore diameter at 0.967 relative pressure; an attrition resistance of 0to 45 Davison Index (DI) as determined by the method disclosed in U.S.Pat. Nos. 3,650,988 and 4,247,420 for fresh material after 2-hour aircalcination at 538° C.; a microcrystalline MgO component before andafter steaming as determined by X-ray diffraction; when used as an SOxcontrol additive, the composition preferably includes a total promotermetal content of 1 to 15 weight percent as oxides, and preferably 2 to10% by weight ceria and/or vanadia; a sodium content of less than about1% by weight Na₂ O, and preferably less than 0.5% by weight Na₂ O; and abimodal distribution of mesopores in the 40-200 Å and 200-2000 Åregions. The median (pore volume basis) pore diameter from nitrogenporosimetry ranges from approximately 50 Å to 100 Å, depending on thefinal calcination condition, e.g., simple air calcination at 538° C. orair calcination at 704° C. with varying levels of steam.

Referring to FIG. 1, it is seen that the composition may be prepared bya multi-step process described as follows:

(1) A solution containing a lanthanum salt such as lanthanum nitrate isreacted with a solution of sodium aluminate under conditions wherein aseparate stream of lanthanum nitrate is combined with a stream of sodiumaluminate solution over a period of 20 to 60 minutes in a stirredreaction vessel to form a lanthanum-aluminum hydrous oxidecoprecipitate.

(2) The coprecipitated lanthanum-aluminum hydrous oxide slurry mixtureof step (1) is aged at a pH of 9.3 to 9.7 for a period of 0.1 to 2 hoursat a temperature of 20° to 65° C.

(3) The aged slurry of step (2) is then reacted with an aqueous solutionof magnesium nitrate and a solution of sodium hydroxide which are addedas separate streams over a period of 20 to 60 minutes to a stirredreaction vessel at a pH of about 9.5 and at a temperature of 20° to 65°C. to obtain a ternary magnesium/lanthanum/aluminum hydrous oxideprecipitate.

(4) The ternary oxide precipitate of step (3) is separated byfiltration, washed with water to remove extraneous salts, preferablyspray dried, and calcined at a temperature of 450° to 732° C. to obtaina ternary oxide base composition that is free of MgAl₂ O₄ spinel andhaving a surface area of 130 to 260 m² /g.

(5) The ternary oxide base obtained in step (4), when used as an SOxadditive, is preferably impregnated with solutions of cerium and/orvanadium, iron and optionally titanium to impart a ceria content ofabout 5 to 15 weight percent and a vanadia and iron content of about 1to 10 weight percent and optionally a titania content of 0 to 10 weightpercent.

(6) The impregnated base of step (5) is then dried and calcined at atemperature of 450° to 700° C.

Alternative methods for preparing the novel compositions are outlined inFIG. 2 wherein: the magnesium/lanthanum/rare earth nitrate, sodiumhydroxide, sodium aluminate solutions described above are combined in amixer (typically a four-port mix-pump) to form a Mg--La/RE--Al ternaryhydrous oxide coprecipitate which is aged for about 10 to 60 minutes andthen further processed into particulate SOx control additives as shownin alternative processing methods (A) and (B).

The preferred compositions of the present invention are prepared in theform of microspheres which have a particle size range of 20 to 200microns and a Davison attrition index (DI) of 0 to 45, preferably 0 to15, and are suitable for use as SOx control additive in FCC processes.

The metals control additive composition may be combined withconventional commercially available FCC catalyst zeolite-containing FCCcatalysts which typically contain 10 to 60 weight percent zeolite suchas Type Y, ultrastable Y, ZSM-5 and/or Beta zeolite dispersed in aninorganic oxide matrix, such as the Octacat®, XP®, Super-D®, and DA®grades produced and sold by W. R. Grace & Co.-Conn.

It is contemplated that the metals control SOx control additivecompositions may also be incorporated in FCC catalyst particles duringmanufacture in a catalyst preparation procedure such as disclosed inU.S. Pat. No. 3,957,689, U.S. Pat. No. 4,499,197, U.S. Pat. No.4,542,118 and U.S. Pat. No. 4,458,623 and Canadian 967,136.

The metals control additive compositions (unpromoted) are typicallyadded to a FCC catalyst in amounts ranging from 0.2 to 15 weight percentand more preferably 0.5 to 5 weight percent. In addition, the catalystcomposition may include about 1 to 15 weight percent of theceria/vanadia promoted compositions for control of SOx emissions. Thepromoted/unpromoted compositions may be pre-blended prior to adding to aFCC unit. In one preferred embodiment, the FCC catalyst will alsocontain a noble metal combustion/oxidation catalyst such as Pt and/or Pdin amounts of 0.1 to 10 ppm. The FCC catalyst/SOx control compositionmixture is reacted with hydrocarbon gas-oil and residual feedstocks thatcontain as much as 2.5 weight percent sulfur (S), 0.005 weight percentNi and/or 0.005 weight percent V, at temperatures of 520° to 1100° C.(cracking reaction) and 700° to 750° C. (regeneration). In typicalcommercial FCC operations it is anticipated that the FCC catalyst mayaccomodate up to about one weight percent Ni and/or V and still containan acceptable level of activity and/or selectivity.

Cracking activity is determined by the so-called microactivity test(MAT) method according to ASTM #D 3907-8.

The Davison Index (DI) is determined as follows:

A sample of catalyst is analyzed to determine the weight of particles inthe 0 to 20 and 20+ micron size ranges. The sample is then subjected toa 1 hour test in a fluid catalyst attrition apparatus using a hardenedsteel jet cup having a precision bored orifice. An air flow of 21 litersa minute is used. The Davison Index is calculated as follows: ##EQU1##

Having described the basic aspects of my invention, the followingexamples are included to illustrate specific embodiments.

EXAMPLE 1

A coprecipitation run was carried out by feeding one acidic stream andone basic stream simultaneously into a high speed mix-pump reactor withmultiports, allowing the viscous product stream to fall into 4000 g ofheel water in a kettle maintained at 38°-40° C. with good agitation. Theacidic feedstream contained 654.4 g of MgO and 413.3 g of La-rich rareearth oxide, all in the form of nitrate in a total volume of 9840 ml.The basic feedstream had a sodium aluminate solution bearing 654.4 g ofAl₂ O₃ along with 320 g of 50 weight percent sodium hydroxide solutionin a total volume of 9840 ml. While these two streams were fed at anequal rate of 400 ml/minute, the feed rate of stream No. 3 with 16weight percent sodium hydroxide solution was adjusted so as to controlpH of the slurry in the kettle at 9.4-9.5. After aging the slurry underthis condition for 15 minutes and confirming pH was at 9.5 at the end ofaging, the slurry was immediately vacuum filtered. The filtercake wasthen homogenized using a high-shear mixer, Drais milled once,rehomogenized, and was spray dried.

A 400 g portion of the above resulting microspheres was slurried once in1000 g of tap water at room temperature for 3 minutes, and then waswashed once with another 1000 g of room-temperature tap water, andfiltered. After overnight drying in a 115° C. oven, the material was aircalcined at 704° C. for 2 hours. Properties of the resulting material,hereafter to be referred to as 1A, are as follows: Chemical composition(weight percent): 36.8% MgO, 20.8% La₂ O₄, 0.1% CeO₂, 23.4% total rareearth oxide, 0.2% Na₂ O, and 39.1% Al₂ O₃. The results from X-ray powderdiffraction scan showed that this material was virtually MgAl₂ O₄spinel-free before and after 5-hour exposure to flowing (1.5liters/minute) air containing 20 volume % steam at 788° C. Averageparticle size: 99 microns, attrition resistance: 17 DI (Davison Index),BET (N₂) surface area: 181 m² /g.

A set of four 60-gram samples was prepared by physically blending anORION® family of Grace Davison FCC catalyst with 0, 5, 10, and 15 weightpercent (on a dry basis) of 1A. Each sample was then treated accordingto the following protocol: Heated to 204° C. and allowed one-hour soakat this temperature in a muffle furnace; Raised at a rate ofapproximately 4° C./minute to 677° C. and then allowed to soak at thistemperature for 3 hours; Cooled to room temperature; Impregnated withvanadium naphthenate in pentane to completely and uniformly cover allparticles with vanadium; Allowed pentane to evaporate away in a mufflefurnace at room temperature; Heated to 204° C. and held for one hour;Charged into an Inconel fluidbed reactor; Steamed for 5 hours in thisfluidized bed at 788° C., with 80 vol. % steam (6.8 g H₂ O/hour) and 20%vol. % air. Each sample was then examined for chemical and physicalproperties, especially the zeolite surface area. The results arepresented in Table I. The data reveal unequivocally that the material 1Ais highly effective in protecting zeolites in the FCC catalyst fromvanadium attack. With only 5 weight percent of 1A in the blend, thezeolites in this blend retained approximately 93% more zeolite area thanwithout 1A. With 10 weight percent of 1A, there is a 122% increase inzeolite area as a result of preferential vanadium capture by thematerial of this invention, 1A.

EXAMPLE 2

Another additive having a composition slightly different from 1A ofExample 1 was prepared in exactly the same manner as in Example 1,except for the feedstream composition. The acidic feedstream consistedof 9840 ml of solution containing 671.6 g of MgO, 275.5 g of La-richrare earth oxide, and 123.1 g of CeO₂, all in the form of nitrate. Thebasic feedstream contained 671.6 g of Al₂ O₃ in the form of sodiumaluminate solution along with 320 g of 50 weight percent sodiumhydroxide solution in a total volume of 9840 ml.

The material obtained from spray drying, slurrying, washing, drying, and2-hour air calcination at 704° C., hereafter to be referred to as 2A,had the following properties: Chemical composition (weight percent):38.0% MgO, 13.8% La₂ O₃, 5.7% CeO₂, 21.1% total rare earth oxide, 0.4%Na₂ O, 0.3% SO₄, and 39.8% Al₂ O₃. This material, 2A, also showedvirtually no MgAl₂ O₄ spinel before and after 5-hour steaming (80%steam/20% air) described in Example 1.

In exactly the same manner as in Example 1, another set of four 60-gramsamples, ORION/2A blend, was prepared, and was treated with the samevanadium impregnation and steaming as described in Example 1. Theresults on this set of blends are presented in Table II. The dataessentially confirm what has already been observed in Example 1.

EXAMPLE 3

A 71.82 g (70.00 g on a dry basis) portion of 2A of Example 2 wassprayed with fine mist of ammoniacal vanadium tartrate solution bearing1.80 g of V₂ O₅ to incipient wetness using an atomizer and a rotarymixer. After allowing the impregnated material to stand at roomtemperature for approximately 30 minutes, the material was oven driedovernight at 115° C., and then was air calcined at 538° C. for one hour.The resulting material, hereafter to be referred to as 3A, was virtuallyMgAl₂ O₄ spinel-free according to X-ray powder diffraction scan beforeand after 48-hour exposure to flowing air (1.5 liters/minute) containing20 vol. % steam at 702° C. The properties of this material are asfollows: Chemical composition (weight percent): 35.9% MgO, 13.5% La₂ O₃,5.6% CeO₂, 20.8% total rare earth oxide, 0.4% Na₂ O, 2.7% V₂ O₅, and39.4% Al₂ O₃. Average particle size: 54 microns, Attrition resistance: 8DI. BET (N₂) surface areas before and after 48-hour steaming (20%steam/80% air) were 181 and 124 m² /g, respectively.

The above resulting material, 3A, was evaluated on the bench as apotential SOx additive, i.e., SOx transfer catalyst, capturing SO₃ inthe oxidizing environment of the regenerator and releasing sulfur in theform of H₂ S in the reducing environment of the riser. Since theperformance of SOx additive can be assessed largely by the capacity ofSO₃ capture and the release capability in the form of H₂ S, thefollowing two tests were carried out for this sample:

(1) Capacity for SO₃ capture: A blend was prepared from 9.950 g ofsteamed (6 hours in a fluidized bed at 760° C. and 5 psig) OCTACAT®(another Grace Davison FCC catalyst) and 0.050 g of fresh 3A, all on adry basis. It was charged into an Inconel reactor having an I.D. of 1.04cm, and was subjected to two-stage treatments: First, a 30-minutereduction in flowing (1.5 liters total/min.) N₂ containing 2 vol. % H₂,and next, a 30-minute oxidation in flowing (1.5 liters total/min. N₂containing 4 vol. % O₂ and 0.0900 vol. % SO₂ at 732° C. After eachtreatment, the sample was discharged, homogenized, and the sulfate levelwas determined on a one-gram portion removed from the sample. The weightpercent SO₄ found in this sample as a result of the oxidation treatmentwas 0.46%. This was taken as a measure of the capacity for SO₃ capture.The capacity found for this sample represents approximately 85% of thetheoretical maximum--the maximum weight percent SO₄ that can beaccumulated in this sample is approximately 0.54% when all metals butaluminum form stoichiometric sulfates at 732° C. The material of thisinvention, 3A, thus has a quite high capacity for SO₃ storage.

(2) Release capability: A 0.40 g sample of fresh 3A was placed in adown-flow Vycor glass reactor, and was exposed to flowing N₂ containing9.50 vol. % O₂ and 0.6000 vol % SO₂ at a total flow rate of 126ml/minute and 732° C. for a period of 3 hours, and cooled in flowing N₂for discharge. A 0.10 g portion of the above-treated sample was examinedby temperature-programmed reduction (TPR)/massspectrometer in aramp-mode at a rate of 20° C./min., using propane at 14.2 ml/min. as areducing agent. During the course of this TPR run, the concentration ofH₂ S was determined as a function of temperature by monitoring massnumber 34. The TPR scan data plot, H₂ S counts vs. temperature for thissample showed an onset temperature--the temperature here represents asort of dynamic temperature rather than equilibrium or steady/isothermaltemperature--of approximately 500° C., which is well below the riserbottom temperature. Thus, 3A is expected to show a release capability.

EXAMPLE 4

Three of the four steamed samples with vanadium listed in Table I forExample 1 were evaluated by microactivity test (MAT) using a fixed bedreactor described in ASTM Method No. D3907. The feedstock employed inMAT evaluation was a sour, imported heavy gas oil with properties shownin Table III. The MAT data at constant conversion summarized in Table IVclearly demonstrate what one can expect from the materials of thisinvention. Namely, there is activity benefit, as reflected in thesubstantially decreased catalyst-to-oil weight ratio (C/O) for the FCCcatalyst samples blended with some of the materials of this invention.There are also selectivity benefits--especially noticeable are thedrastically lowered coke and H₂ gas yields and substantially increasedgasoline yield.

EXAMPLE 5

An additive with a composition very slightly different from 2A wasprepared in exactly the same manner as in Example 2 by making minorchanges in Mg/rare earth/Al ratio for the feedstreams. The materialobtained from spray drying, followed by slurrying, washing, drying, and2-hour calcination at 538° C., hereafter to be referred to as 5A, hadthe following properties: Chemical composition (weight percent): 39.1%MgO, 12.0% La₂ O₃, 7.4% CeO₂, 20.7% total rare earth oxide, 0.1% Na₂ O,0.3% SO₄, and 39.6% Al₂ O₃. Some of the physical properties are--0.67g/cc average bulk density, 73 micron average particle size, 187 m² /BET(N₂) surface area, 0.485 N₂ pore volume, 66 Å median (N₂ -PV) porediameter, and 10 DI.

A set of three 60-gram samples of ORION®/5A blend was prepared, and wassteamed with vanadium in exactly the same manner as in Example 1.Properties and MAT data at constant conversion for these samples arepresented in Tables V and VI, respectively. These data essentiallyconfirm the kind of results we have already shown in Tables I and IV forthe materials of this invention.

EXAMPLE 6

A co-precipitation run was carried out by simultaneously feeding twofeedstreams, one acidic, the other basic, into a high speed mix-pumpreactor with multi-ports, allowing the viscous outlet stream to fallinto 4000 g of heel water in a kettle which was maintained at 38°-39°0C. with good agitation. The acidic feedstream contained 688.8 g of MgO,223.9 g of La-rich rare earth oxide, and 120.6 g of CeO₂, all in theform of nitrate in a total volume of 9840 ml. The basic feedstream had asodium aluminate solution bearing 688.8 g of Al₂ O₃ along with 448 g of50 weight percent sodium hydroxide solution in a total volume of 9840ml. While these two feedstreams were pumped into the mix-pump reactor atan equal rate of 400 ml/minute, the resulting slurry in the kettle wasmaintained at 9.5 pH and 38°-39° C., feeding a 16 weight percent sodiumhydroxide solution directly into the kettle throughout the run. Afterallowing the slurry to age under this condition for 15 minutes, pH ofthe slurry was raised to 9.6 using 16 weight percent sodium hydroxidesolution, and then the slurry was immediately dewatered. The filtercakewas homogenized, Drais milled once, rehomogenized, and then was spraydried.

A portion of the above resulting microspheres weighing 450 g wasslurried once in 1125 g of tap water at room temperature for 3 minutes,dewatered, washed once with another 1125 g of room-temperature tapwater, and then was dewatered. After overnight drying in a 115° C. oven,the material was air calcined at 704° C. for 2 hours. The resultingmaterial, hereafter to be referred to as 6A, had the followingproperties: Chemical composition (weight percent); 39.02% MgO, 12.01%La₂ O₃, 1.17% Nd₂ O₃, 6.70% CeO₂, 19.97% total RE₂ O₃, 0.23% Na₂ O,0.04% Fe₂ O₃, 0.19% SO₄, and 40.05% Al₂ O₃.

An 80.51 g (80.00 g on a dry basis) portion of 6A was sprayed with finemist of ammonium-vanadium citrate solution bearing 2.05 g of V₂ O₅ toincipient wetness using an atomizer and a rotary mixer. After allowingthe impregnated material to stand at room temperature for approximately30 minutes, the material was oven dried overnight at 115° C., and thenwas air calcined at 538° C. for one hour. The resulting catalyst,hereafter to be referred to as 6B, was virtually MgAl₂ O₄ spinel-freeaccording to X-ray powder diffraction scan before and after steaming--a48-hour exposure to flowing air (1.5 liters/minute) containing 20 vol. %steam at 704° C. This catalyst has also been characterized by thefollowing properties: Chemical composition (weight percent): 37.96% MgO,11.68% La₂ O₃, 1.17% Nd₂ O₃, 6.52% CeO₂, 19.43% total RE₃ O₃, 0.22% Na₂O, 0.04% Fe₂ O₃, 0.18% SO₄, 38.96% Al₂ O₃ and 2.72% V₂ O₅ . Physicalproperties: 0.62 g/cc average bulk density, 88 micron average particlesize, 16 DI, 155 m² /g surface area, 0.42 cc/g nitrogen pore volume, and85 Å median pore diameter (N₂ -PV basis).

EXAMPLE 7

A catalyst virtually identical to 6B in Example 6 was prepared inexactly the same manner as in Example 6 using the same formulation andprocedure. A sample of blend consisting of 0.5 weight percent of thiscatalyst and 99.5 weight percent of ORION®-842 (one of theGRACE-Davison's family of FCC catalysts) equilibrium catalyst wasprepared. This blend was pilot tested for 24 hours in a DavisonCirculating Riser unit for assessing SOx removal efficiency using a gasoil containing 1.49 weight percent sulfur.

A 60 g portion of the above-tested sample was subjected to a so-calledsink/float separation in order to separate the heavier particles (thenon-FCC catalyst fraction that has picked up most of SO₃) from thelighter ones (the FCC catalyst particles which picked up very littleSO₃) as follows: (1) First, by mixing with high-density (2.96 g/cc atroom temperature) organic liquid medium (e.g., tetrabromoethane) toallow the entire particles to float, (2) next, by adding an appropriateamount of relatively low-density organic liquid medium (e.g.tetrachloroethane) that is miscible with the higher-density medium sothat the relatively heavier particles will sink while the rest willremain floating or suspended, and (3) finally, by centrifuging, e.g., at2000 RPM, followed by decantation. A sufficient quantity of sinkfraction was obtained by repeating this separation procedure. Theprominent phases present in the sink fraction identified by X-ray powderdiffraction scan were β-MgSO₄ and transitional aluminas. Thisdemonstrates the chemical consequence of magnesia component of thematerial of this invention when subjected to real FCC conditions.

EXAMPLE 8

Another co-precipitation run was carried out in exactly the same manneras in Example 6, using a slightly different feed-stream this time toinclude vanadium in the run-off. The acidic feedstream had 688.8 g ofMgO, 223.9 g of La-rich rare earth oxide, and 120.5 g of CeO₂, all inthe form of nitrate in a total volume of 9840 ml. Included also in thisacidic feedstream was 46.0 g of V₂ O₅ in the form of ammonium-vanadiumcitrate. The basic feedstream consisted of a sodium aluminate solutioncontaining 688.8 g of Al₂ O₃ along with 384 g of 50 weight percentsodium hydroxide solution in a total volume of 9840 ml. A 1000 g portionof washed filtercake was oven-dried overnight at 115° C. The resultingcake was crushed and sifted to have 100-325 mesh particles. The catalystobtained by one-hour air calcination at 450° C., hereafter to bereferred to as 8A, had the following properties: Chemical composition(weight percent): 38.12% MgO, 11.14% La₂ O₃, 1.29% Nd₂ O₃, 6.73% CeO₂,19.64% total RE₂ O₃, 0.12% Na₂ O, 0.01% Fe₂ O₃, 0.13% SO₄ 39.18% Al₂ O₃,and 2.63% V₂ O₅. This catalyst was found to be MgAl₂ O₄ spinel-freebefore and after 48-hour steaming (20% steam/80% air) at 704° C.according to the results of powder X-ray diffraction scan. BET (N₂)surface areas before and after the steaming are 223 and 133 m² /grespectively.

EXAMPLE 9

In exactly the same manner as in Example 8, this co-precipitation runwas carried out to include iron in the run-off. The acidic feedstreamcontained 688.8 g of MgO, 195.9 g of La-rich rare earth oxide, 103.7 gof CeO₂, and 39.6 g of Fe₂ O₃, all in the form of nitrate in a totalvolume of 9840 ml. The basic feedstream contained a sodium aluminatesolution bearing 688.8 g of Al₂ O₃ along with 576 g of 50 weight percentsodium hydroxide solution in a total volume of 9840 ml. After spraydrying and washing in the same manner as in Example 6, the material wasdried for 30 minutes in a 204° C. preheated oven, and then was aircalcined in a preheated furnace at 732° C. for 30 minutes. The resultingcatalyst, hereafter to be referred to as 9A, had the followingproperties: Chemical composition (weight percent): 39.73% MgO, 10.29%La₂ O₃, 1.04% Nd₂ O₃, 5.82% CeO₂, 17.21% total RE₂ O₃, 0.46% Na₂ O.2.25% Fe₂ O₃, 0.11% SO₄, and 39.91% Al₂ O₃. Physical properties: 0.57g/cc average bulk density, 91 micron average particle size, 32 DI, 156m² /g surface area, 0.57 cc/g nitrogen pore volume, and 91 Å median porediameter (N₂ -PV basis). Powder X-ray diffraction scan showed that thismaterial was MgAl₂ O₄ spinel-free.

A 70.40 g (70.00 g on a dry basis) portion of 9A was sprayed with 57.70g of ferric oxalate solution bearing 1.46 g of Fe₂ O₃, using an atomizerand a rotary mixer. After allowing the impregnated material to stand atroom temperature for 30 minutes, the material was dried once again in a204° C. preheated oven, and then was air calcined in a 538° C. preheatedfurnace for 30 min. The resulting catalyst, hereafter to be referred toas 9B, had the following properties: Chemical composition (weightpercent): 38.32% MgO, 10.39% La₂ O₃, 1.06%Nd₂ O₃, 5.74% CeO₂, 17.25%total RE₂ O₃, 0.47%Na₂ O, 4.29% Fe₂ O₃, 0.22% SO₄, and 39.10% Al₂ O₃.Physical properties: 0.62 g/cc average bulk density, 91 micron averageparticle size, 21 DI, 177 m² /g surface area, 0.576 cc/g nitrogen porevolume, and 80 Å median pore diameter (N₂ -PV basis). Powder X-raydiffraction pattern of 9B was also MgAl₂ O₄ spinel-free.

Another portion of 9A weighing 80.33 g (80.00 g on a dry basis) wassprayed to incipient wetness with 58.40 g ammonium-vanadium citratesolution bearing 2.05 g of V₂ O₅. After allowing the impregnatedmaterial to stand at room temperature for 30 minutes, the material wasdried in a 204° C. preheated oven, and then was air calcined in a 538°C. preheated furnace for 30 minutes. The resulting catalyst, hereafterto be referred to as 9C, showed the following properties: Chemicalcomposition (weight percent): 38.73% MgO, 10.14% La₂ O₃, 1.03% Nd₂ O₃,5.73% CeO₂, 16.95% total RE₂ O₃, 0.47% Na₂ O, 2.19% Fe₂ O₃, 0.12% SO₄,and 38.61% Al₂ O₃. Physical properties: 0.56 g/cc average bulk density,86 micron average particle size, 29 DI, 161 m² /g surface area, 0.554cc/g nitrogen pore volume, and 111 Å median pore diameter (N₂ -PVbasis). X-ray powder diffraction scan revealed that this material alsowas MgAl₂ O₄ spinel-free.

EXAMPLE 10

Substituting chlorides for all nitrates, otherwise in exactly the samemanner as in Example 6, a co-precipitation run was carried out to obtaina material having the same chemical composition as 6A, except in rareearth distribution. In order to wash chloride out of the spray driedparticles, the following wash scheme was employed: 225 g of the spraydried material was slurried in 600 g of room-temperature tap water for 5minutes; dewatered. It was then reslurried in 450 ml of 75° C., 3 weightpercent ammonium carbonate solution for 10 minutes; dewatered. Aftertwice washing with 450 ml of 75° C., 3 weight percent ammonium carbonatesolution and dewatering; and three times rinsing with 450 ml of 75° C.tap-water and dewatering, the material was subjected to 45-minute dryingin a preheated oven at 204° C., followed by 45-minute calcination in apreheated furnace at 704° C.

An 81.22 g (80.00 g on a dry basis) portion of the above-calcinedmaterial was sprayed with 49.71 g of ammonium-vanadium citrate solutionbearing 2.05 g of V₂ O₅. After allowing the material to stand at roomtemperature for 30 minutes, it was air calcined for 45 minutes in a 538°C. preheated furnace. The resulting catalyst, hereafter to be referredto as 10A, had the following properties: Chemical composition (weightpercent ): 37.88% MgO, 8.88% La₂ O₃, 2.71% Nd₂ O₃, 6.45% CeO₂, 19.18%total RE₂ O₃, 0.22% Na₂ O, 0.06% Fe₂ O₃, 0.27% SO₄, 38.55% Al₂ O₃, and2.67% V₂ O₅. Physical properties: 0.66 g/cc average bulk density, 69micron average particle size 12 DI, 150 m² /g surface area, 0.438 cc/gnitrogen pore volume, and 100 Å median pore diameter (N₂ -PV basis).X-ray powder diffraction scan revealed the absence of MgAl₂ O₄ spinel in10A.

EXAMPLE 11

Another co-precipitation run was carried out in exactly the same manneras in Example 8, substituting chlorides for all nitrates as follows: Theacidic feedstream had 688.8 g of MgO, 198.0 g of La-rich rare earthoxide, 108.5 g of CeO₂, and 37.9 g of Fe₂ O₃, all in the form ofchloride in a total volume of 9840 ml. The basic feedstream contained asodium aluminate solution bearing 688.8 g of Al₂ O₅ along with 672 g of50% NaOH solution in a total volume of 9840 ml. The spray dried materialwas washed, dried, and calcined in exactly the same manner as in Example10.

A portion of the above-calcined material weighing 81.01 g (80.00 g on adry basis) was sprayed with 45.85 g of ammonium-vanadium citratesolution bearing 2.05 g of V₂ O₅. After allowing the material to standat room temperature for 30 minutes, the material was air calcined at538° C. for 45 minutes in a preheated furnace. The resulting catalyst,hereafter to be referred to as 11A, had the following properties:Chemical composition (weight percent): 38.88% MgO, 7.49% La₂ O₃,2.42%Nd₂ O₃, 6.05% CeO₂, 17.01% total RE₂ O₅, 0.17% Na₂ O, 2.14% Fe₂ O₃,0.25% SO₄, 38.19% Al₂ O₃, and 2.62% V₂ O₅. Physical properties: 0.67g/cc average bulk density, 73 micron average particle size, 12 DI, 150m² /g surface area, 0.436 cc/g nitrogen pore volume, and 97 Å medianpore diameter (N₂ -PV basis). Powder X-ray diffraction scan showed that11A was spinel-free.

EXAMPLE 12

Materials prepared in Examples 6 and 8-11 were evaluated for theircapability to oxidize SO₂ and to store SO₃ as well as for their H₂ Srelease capability as follows: First, each of the fresh samples wassubjected to SO₂ plus air, and then was exposed to flowing propane asthe sample temperature was linearly increased. The concentration of H₂ Sgiven off was detected by a mass-spectrometer as a function oftemperature. For example, a 0.40 g sample of fresh 6A was placed in adown-flow Vycor glass reactor, and was exposed to flowing N₂ containing9.50 vol. % O₂ and 0.6000 vol. % SO₂ at a total flow rate of 126ml/minute and 732° C. for a period of 3 hours, and cooled in flowing N₂for discharge. A 0.10 g portion of thus treated sample was examined bytemperature-programmed reduction (TPR) reaction/mass-spectrometer in aramp-mode at a rate of 23° C./minute, using propane at 14.2 ml/minute asa reducing agent. The concentration of H₂ S (weight % H₂ S with respectto sample weight) released was determined as a function of temperatureby monitoring mass number 34. Results taken from four sets of TPR scandata plots, H₂ S counts vs. temperature for different samples aresummarized in Table VII. Typically, the H₂ S counts vs. temperature plotshows a peak in the vicinity of 680° C. Therefore, the cumulative amount(area under the peak expressed as weight % H₂ S relative to sampleweight) of H₂ S released up to this temperature and two lower levels oftemperatures was taken as a measure of the release capability.Well-promoted samples generally show low onset temperatures for the H₂ Srelease as well as sharp increase in the rate of subsequent release. Therelease virtually ends at approximately 800° C. Hence, the cumulative H₂S released up to 800° C. was taken as a measure of the extent of SO₂oxidation achieved over 3-hour period. The data reveal the following:(1) Results from sample Set 2 show that iron is not as good a promoteras vanadium at the same atom % loading; (2) Results from Sample Set 3show that the best promotion can be achieved when the Ce-promoted baseis further promoted with both Fe and V; (3) Data from Sample Set 4reveal that the process of making the material of this invention is notlimited to using nitrates as the source of nagnesium, rare earth, andiron.

EXAMPLE 13

A batch of spray-dried material identical to Example 10 in formulationas well as in coprecipitation method was prepared in exactly the samemanner as in Example 10. A 450 g portion of the spray dried particleswas slurried in 1125 g of room-temperature tap water for 3 minutes; anddewatered. It was reslurried in 1125 g of 80° C. water for 10 minutes,maintaining pH of the slurry at 8.5 using ammonium hydroxide. Finally,rinsed three times with 1125 g of 80° C. water and dewatered. After30-minute drying in a 204° C. preheated oven, the material was subjectedto 3-hour calcination in flowing air at 593° C. The resulting material,hereafter to be referred to as 13A, had the following properties:Chemical composition (weight percent): 39.54% MgO, 9.07% La₂ O₃,2.70%Nd₂ O₂, 6.79% CeO₂, 19.69% total RE₂ O₃, 0.20 Na₂ O, 0.21% Fe₂ O₃, 0.23%SO₄, and 39.92% Al₂ O₃. Physical properties: 160 m² /g surface area,0.545 cc/g nitrogen pore volume, and 120 Å median pore diameter (N₂ -PVbasis).

EXAMPLE 14

Another batch of spray-dried material identical to Example 11 informulation as well as in coprecipitation method was prepared in exactlythe same manner as in Example 11. A 450 g portion of the spray-driedparticles was washed, dried, and calcined in the same manner as inExample 11. The resulting material, hereafter to be referred to as 14A,had the following properties: Chemical composition (weight percent):39.56% MgO, 8.06% La₂ O₃, 2.61% Nd₂ O₃, 6.05% CeO₂, 17.84% total RE₂ O₃,0.17% Na₂ O, 1.96% Fe₂ O₃, 0.21% SO₄, and 39.98% Al₂ O₃. Physicalproperties: 0.66 g/cc average bulk density, 86 micron average particlesize, 21 DI, 156 m² /g surface area, 0.484 cc/g nitrogen pore volume,and 105 Å median pore diameter (N₂ -PV basis).

EXAMPLE 15

For the purpose of demonstrating the efficiency of the above-preparedmaterials, 13A and 14A, for trapping vanadium in FCC operation, thefollowing study was carried out: a 60-gram sample was prepared byphysically blending an ORION® family of Grace-Davison FCC catalyst with10 weight percent (on a dry basis of 13A. In the same manner, anothersample was prepared using 14A. The third sample containing no additive,i.e., unblended FCC catalyst, served as the base case. Each sample wasthen treated according to the following protocol: Heated to 204° C. andallowed one-hour soak at this temperature in a muffle furnace; raised ata rate of approximately 4° C. per minute to 677° C. and then allowed tosoak at this temperature for 3 hours; cooled to room temperature;impregnated with vanadium naphthenate in pentane to completely anduniformly cover all particles with vanadium; allowed pentane toevaporate away in a muffle furnace at room temperature; heated to 204°C. and held for one hour; charged into an Inconel fluid-bed reactor;steamed for 5 hours in this fluidized bed at 788° C., with 80 vol %steam (6.8 g H₂ O/hour) and 20 vol % air. Each sample was then examinedfor chemical and physical properties, especially the zeolite surfacearea. The results are presented in Table VIII. Each sample was alsoevaluated by microactivity test (MAT) using a fixed bed reactoraccording to ASTM Method No. D3907. The feedstock employed in MATevaluation is shown in Table IX. The MAT results summarized in Table Xclearly demonstrate that the material of this invention, with or withoutiron included in the composition, is an efficient vanadium trap.

                  TABLE I                                                         ______________________________________                                        Effect of Additive 1A on FCC Catalyst                                         ______________________________________                                        Blend (Wt.) Ratio                                                                          0/100   5/95      10/90 15/85                                    1A/FCC Cat.                                                                   Chemical Composition (wt. %) after steaming with vanadium                     Al.sub.2 O.sub.3                                                                           32.63   33.02     33.35 33.44                                    Na.sub.2 O   0.43    0.42      0.42  0.39                                     SO.sub.4     0.51    1.11      1.27  1.07                                     MgO          0.08    2.38      3.98  6.00                                     RE.sub.2 O.sub.3                                                                           1.51    2.79      3.76  5.02                                     Ni           0.003   0.002     0.003 0.002                                    V            0.522   0.568     0.550 0.560                                    Properties after steaming with vanadium                                       Unit Cell, Å                                                                           24.23   24.23     24.24 24.23                                    Pk. Ht.      12      19        25    24                                       Total S.A., m.sup.2 /g                                                                     68      114       127   129                                      Zoolite B.A., m.sup.2 /g                                                                   45      83        90    89                                       ______________________________________                                    

                  TABLE II                                                        ______________________________________                                        Effect df Additive 2A on FCC Catalyst                                         ______________________________________                                        Blend (Wt.) Ratio                                                                          0/100   5/95      10/90 15/85                                    2A/FCC Cat.                                                                   Chemical Composition (wt. %) after steaming with vanadium                     Al.sub.2 O.sub.3                                                                           32.52   32.82     32.67 34.26                                    Na.sub.2 O   0.44    0.43      0.42  0.43                                     SO.sub.4     0.49    1.08      1.07  1.01                                     MgO          0.08    2.30      4.18  5.77                                     RE.sub.2 O.sub.3                                                                           1.51    2.60      3.57  4.53                                     Ni           0.002   0.003     0.003 0.003                                    V            0.495   0.548     0.542 0.537                                    Properties after steaming with vanadium                                       Unit cell, Å                                                                           24.23   24.24     24.26 24.24                                    Pk. Ht.      19      30        34    36                                       Total S.A., m.sup.2 /g                                                                     81      127       143   149                                      Zoolite B.A., m.sup.2 /g                                                                   53      87        99    102                                      ______________________________________                                    

                  TABLE III                                                       ______________________________________                                        Properties of Sour, Imported, Heavy Gas Oil (SIHGO)                           ______________________________________                                        API gravity at 16° C.                                                                      22.5                                                      Sulfur (wt. %)      2.6                                                       Nitrogen (wt. %)    0.086                                                     Conradson Carbon (wt. %)                                                                          0.25                                                      Aniline Point (°C.)                                                                        73                                                        K Factor            11.6                                                      D-1160 (° C.)                                                          IBP                 217                                                        5                  307                                                       10                  324                                                       20                  343                                                       40                  382                                                       60                  423                                                       80                  472                                                       90                  500                                                       95                  524                                                       ______________________________________                                    

                  TABLE IV                                                        ______________________________________                                        Interpolated, Mass-Balanced MAT Yields at 55 wt. % Conversion                 Samples: 5h/788° C. Steamed (80% steam/20% air at 0 psig)              1A/ORION ® Blends with 5000 ppm V                                         Test Conditions: 527° C., 30 sec. Contact Time, SIHGO                  ______________________________________                                        Feed                                                                          Blend wt. Ratio   0/100     5/95   10/90                                      1A/FCC Cat.                                                                   Cat./Oil Weight Ratio                                                                           5.5       3.5    3.1                                        MAT Yields @ 55% Conversion                                                   H.sub.2           0.95      0.52   0.36                                       C.sub.1 + C.sub.2 's                                                                            2.3       1.8    1.6                                        C.sub.3 ═     2.8       3.0    3.1                                        Total C.sub.3 's  3.4       3.5    3.6                                        C.sub.4 ═     3.8       4.0    4.1                                        iso C.sub.4       1.2       1.6    1.8                                        Total C.sub.4 's  5.5       6.1    6.4                                        C.sub.5.sup.+  Gasoline                                                                         36.1      38.6   39.4                                       LCO               26.6      26.4   26.0                                       640 + Bottoms     18.4      18.6   19.0                                       Coke              6.7       4.4    3.5                                        GC-RON            92.6      91.6   91.0                                       GC-MON            81.3      80.5   80.3                                       n-Paraffins       4.5       4.7    4.5                                        iso-Paraffins     24.1      26.7   28.5                                       Olefins           26.5      25.5   25.3                                       Aromatics         36.2      33.8   31.9                                       Napthenes         8.5       9.4    9.9                                        ______________________________________                                    

                  TABLE V                                                         ______________________________________                                        Effect of Additive 5A on PCC Catalyst                                         ______________________________________                                        Blend (Wt.) Ratio                                                                           0/100      5/95    10/90                                        5A/FCC Cat.                                                                   Chemical Composition (wt. %) after steaming with vanadium                     Al.sub.2 O.sub.3                                                                            32.28      32.86   33.26                                        Na.sub.2 O    0.43       0.42    0.39                                         SO.sub.4      0.50       1.07    1.08                                         MgO           0.11       2.25    4.31                                         RE.sub.2 O.sub.3                                                                            1.53       2.60    3.66                                         Ni            0.002      0.003   0.002                                        V             0.511      0.525   0.537                                        Properties after steaming with vanadium                                       Unit Cell, Å                                                                            24.23      24.24   24.25                                        Pk. Ht.       21         32      35                                           Total S.A., m.sup.2 /g                                                                      91         124     138                                          Zeolite S.A., m.sup.2 /g                                                                    62         88      96                                           ______________________________________                                    

                  TABLE VI                                                        ______________________________________                                        Interpolated, Mass-Balanced MAT Yields at 60 wt. % Conversion                 Samples: 5h/788°C. Steamed (80% steam/20% air at 0 psig)               5A/FCC Catalyst Blends with 5000 ppm V                                        Test Conditions: 527°C., 30 sec. Contact Time, SIHGO                   ______________________________________                                        Feed                                                                          Blend wt. Ratio                                                                              0/100      5/95   10/90                                        5A/FCC Cat.                                                                   Cat./Oil Weight Ratio                                                                        5.4        4.3    3.6                                          H.sub.2        0.98       0.73   0.46                                         C.sub.1 + C.sub.2 's                                                                         2.4        2.1    1.9                                          C.sub.3 ═  3.2        3.3    3.4                                          Total C.sub.3 's                                                                             3.8        4.0    4.1                                          C.sub.4 ═  4.2        4.3    4.4                                          iso C.sub.4    1.5        1.8    2.1                                          Total C.sub.4 's                                                                             6.2        6.6    7.0                                          C.sub.5.sup.+  Gasoline                                                                      39.6       40.8   41.6                                         LCO            25.1       24.7   24.5                                         640 + Bottoms  14.9       15.3   15.5                                         Coke           7.1        5.8    4.8                                          GC-RON         92.1       91.4   90.9                                         GC-MON         81.2       80.9   80.6                                         n-Paraffins    4.6        4.9    4.5                                          i-Paraffins    27.5       29.5   31.1                                         Olefins        22.5       21.6   21.2                                         Aromatics      37.7       36.2   34.5                                         Napthenes      7.7        8.3    9.0                                          ______________________________________                                    

                  TABLE VII                                                       ______________________________________                                        H.sub.2 S Released from SO.sub.3 -Saturated Samples                           in Ramp-mode TPR using Propane                                                                      Amt. of H.sub.2 S                                       Sample   Release Onset                                                                              Released.sup.a vs. Temp. (°C.)                   No.   Set    Temp. (°C.)                                                                         630  655    680  800                                ______________________________________                                        6B    1      490          1.4  2.7    5.3  10.3                               6A    2      625          0.0  0.3    1.2  10.1                               8A    2      490          2.0  4.0    7.1  12.3                               9A    2      560          1.2  2.3    4.2  11.2                               9A    3      560          1.1  2.2    3.9  11.2                               9B    3      560          1.1  2.5    4.8  11.3                               9C    3      475          2.3  4.6    7.4  11.8                               10A   4      490          1.9  3.9    6.6  10.6                               10A   4      450          2.2  4.4    7.3  11.9                               ______________________________________                                         .sup.a Cumulative amount (weight %) of H.sub.2 S released up to the           temperature indicated with respect to the weight of sample tested.       

                  TABLE VIII                                                      ______________________________________                                        Properties of 10% Additive/90% FCC Catalyst Blends                            After Steaming with Vanadium                                                  Additive         None      13A     14A                                        ______________________________________                                        Chemical Composition (wt. %)                                                  Al.sub.2 O.sub.3 32.20     33.14   32.96                                      Na.sub.2 O       0.44      0.41    0.41                                       SO.sub.4         0.49      1.06    1.05                                       MgO              0.08      4.39    4.30                                       Fe.sub.2 O.sub.3 0.55      0.52    0.70                                       RE.sub.2 O.sub.3 1.49      3.47    3.25                                       Ni               0.003     0.003   0.003                                      V                0.561     0.571   0.561                                      Properties                                                                    Unit Cell, Å 24.22     24.24   24.25                                      Pk. Ht.          20        40      40                                         Total S.A., m.sup.2 /g                                                                         84        148     147                                        Zoolite S.A., m.sup.2 /g                                                                       59        107     106                                        ______________________________________                                    

                  TABLE IX                                                        ______________________________________                                        Properties of Gas Oil Feed/Employed in MAT Evaluation                         ______________________________________                                        API gravity at 16° C.                                                                       21.4                                                     Sulfur (wt. %)       0.3                                                      Total Nitrogen (wt. %)                                                                             0.14                                                     Basic Nitrogen (wt. %)                                                                             0.029                                                    Conradson Carbon (wt. %)                                                                           4.8                                                      Aniline Point (°C.)                                                                         97                                                       K-Factor             11.9                                                     D-2887 Simulated Distillation                                                 (Vol. %, °C. at 1 atm)                                                 IBP                  269                                                       5                   337                                                      10                   368                                                      20                   399                                                      40                   454                                                      60                   509                                                      80                   583                                                      90                   637                                                      95                   680                                                      ______________________________________                                    

                  TABLE X                                                         ______________________________________                                        Interpolated, Mass-Balanced MAT Yields at 65 wt. % Conversion                 Samples: 5h/788° C. steamed (80% steam/20% air at 0 psig)              10% Additive/90% FCC Catalyst Blends with 0.56% V                             Test Conditions: 527° C., 30 sec. contact time, Feed (TABLE III)       Additive          None      13A    14A                                        ______________________________________                                        Cat./Oil Weight Ratio                                                                           4.5       2.5    2.5                                        MAT Yields at 65% Conversion                                                  H.sub.2           0.75      0.36   0.42                                       C.sub.1 + C.sub.2 2.3       1.9    1.8                                        C.sub.3 ═     3.1       3.3    3.3                                        Total C.sub.3     3.9       4.0    4.0                                        C.sub.4           4.4       4.2    4.3                                        iC.sub.4          1.5       2.1    2.0                                        Total C.sub.4     6.5       6.8    6.8                                        C.sub.5.sup.+  Gasoline                                                                         43.2      46.4   46.3                                       LCO               19.4      19.1   19.2                                       640 + Bottoms     15.6      15.9   15.8                                       Coke              8.2       5.4    5.6                                        GC-RON            89.9      88.4   88.6                                       GC-MON            79.4      78.6   78.7                                       n-Paraffins       5.3       5.6    5.6                                        i-Paraffins       28.8      32.2   31.7                                       Olefins           24.3      22.9   23.3                                       Aromatics         31.7      28.5   28.5                                       Naphthenes        9.6       10.8   11.0                                       ______________________________________                                    

I claim:
 1. A composition for the passivation of metals and/or controlof SOx emissions in FCC process comprising:(a) a coprecipitated ternaryoxide composition having the formula: 30 to 50 MgO/5 to 30 La₂ O₃ /30 to50 Al₂ O₃ wherein the amounts of MgO, La₂ O₃ and Al₂ O₃ are expressed asweight percent, and the MgO is present as a microcrystalline component;and (b) the composition of (a) combined with approximately 1 to 15weight percent of promoters for SO₂ oxidation and/or H₂ S releaseselected from the oxides of Ce, Pr, Ti, Nb, V, Fe and mixtures thereof.2. The composition of claim 1 further characterized by the absence of aspinel phase, a surface area of 100 m² /g to 300 m² /g, and a Na₂ Ocontent of below about 1% by weight.
 3. The composition of claim 2wherein the surface area is 130 to 200 m² /g.
 4. The composition ofclaim 2 having a surface area of 100 to 150 m² /g after heating to 704°C. for 48 hours in the presence of 20% steam/80% air.
 5. The compositionof claim 1, combined with an FCC catalyst.
 6. The composition of claim 1wherein said La₂ O₃ is derived from a La-enriched rare earth mixture. 7.The composition of claim 5 wherein the FCC catalyst includes anoxidation catalyst selected from the group consisting of Pt, Pd andmixtures thereof.
 8. The composition of claim 5 wherein the FCC catalystcomprises a zeolite selected from the group consisting of Type Y,ultrastable Y, ZSM-5, Beta and mixtures thereof dispersed in aninorganic oxide matrix.
 9. A method for passivating V and Ni and/orcontrolling SOx emissions from an FCC catalyst regeneration processwhich comprises catalytically cracking metals and/or sulfur containinghydrocarbon in the presence of the composition of claim 5 or
 6. 10. Themethod of claim 9 wherein said feedstock contains V and/or Ni and theFCC catalyst includes:a coprecipitated ternary oxide composition havingthe formula: 30 to 50 MgO/5 to 30 La₂ O₃ /30 to 50 Al₂ O₃ wherein theamounts of MgO, La₂ O₃ and Al₂ O₃ are expressed as weight percent, andthe MgO is present as a microcrystalline component.